As an individual ages, the eye is less able to accommodate, or bend the natural lens, to focus on objects that are relatively near to the observer. This condition is known as presbyopia. Similarly, for persons who have had their natural lens removed and an intraocular lens inserted as a replacement, the ability to accommodate is totally absent.
Among the methods used to correct for the eye's failure to accommodate is the mono-vision system in which a person is fitted with one contact lens for distance vision and one lens for near vision. The mono-vision system permits the wearer to distinguish both distance and near objects, but is disadvantageous in that a substantial loss in depth perception results. Thus, a need exists for lenses that both provide correction for the wearer's inability to accommodate and that overcomes some of the disadvantages of known lenses.